How can I tell what SpamAssassin is doing / if a SpamAssassin feature is enabled?

The first thing to do is to run with debugging on. For "spamassassin" and "spamd", add a "-D" parameter. spamassassin -tD < [message_file] This will usually tell you what you want to know.

The best messages to use for this test are the samples included with the distribution, [http://spamassassin.org/full/3.0.x/dist/sample-spam.txt sample-spam.txt] and [http://spamassassin.org/full/3.0.x/dist/sample-nonspam.txt nonspam.txt].